Jul 30, 2012

Modeling Physics First for Modeling Chemistry

A Physics First course based in Modeling Instruction provides an opportunity to rebuild a science curriculum school-wide, with stronger conceptual connections across subject lines and a more cohesive high school science experience.

As I mentioned in my latest post, I just finished a Modeling Instruction workshop last week, and my head is still buzzing with new ideas on physics teaching. Some of the other workshop participants are lucky enough to be attending the 2012 AAPT Summer Meeting in Philadelphia. Due to some extremely poor planning on my part (misinterpreting the "6" in the advance registration deadline date to mean July for one... doh!), I won't be attending the conference itself, but since I've got a few friends down in Philly that I haven't seen for a while, I decided to take a short pilgrimage to the City of Rocky (and say hello to some physics teachers while I'm down there, of course!). In any case, I wanted to make a plug for a poster presentation (tonight, Monday 7/30, at 8:30 at the Houston Hall Bistro) by one co-leader of our NYC Modeling workshop, AMTA President Mark Schober. The poster is titled, "Physics Education Through the Lens of Chemistry Education," and its focus is on examining the benefits of Modeling-based Physics First as a foundation for larger transition within a science department.

I visited Mark's school last spring, and sat in on both some physics and chemistry classes taught to Sophomores and Juniors, respectively (Mark's been advocating for a shift in sequence to full Physics First, rather than the rather unique BPC ordering currently in place, but this transition may take some time to implement.). This past year was Mark's first at the school, and although the chemistry classes have been taught by Modelers for some time, Mark is the first teacher to teach physics using exclusively a Modeling method. In the physics class I saw, Mark began with some discussion about a test on the just-completed circuits unit, in which students got into a heated discussion about a question about a classic circuits puzzler similar to arrangement shown here. Mark gave students time to discuss their various solutions, and gradually the students who had struggled with the solution came around to better understanding. After this discussion, Mark moved on to whiteboarding Worksheet 1 of the Models of Light curriculum, which develops some basic properties of electromagnetic radiation. (The basics of this curriculum were nicely summarized in a presentation given by Kofi Donnelly at EdCampNYC 2012. A screencast of this presentation can be found here.)

Earlier that day, I sat in on a Modeling-based chemistry class where students were studying solubility. In addition to playing around with an awesome PhET simulation on solubility of salts (shown here), they had just completed a lab in which they used a conductivity probe to investigate the change in solubility as different substances were mixed into a sample of distilled water. While students were preparing whiteboards on their results from this lab, I had a chance to chat with a few groups, and it was obvious to me that each student understood clearly that conductivity could be used as evidence of a presence of free ions in a solution. Interestingly, however, no student I talked to could articulate why this connection was valid. That is, when I asked them to tell me what they knew about conductivity, they told me about electrons moving in a wire, through bulbs, etc. When I asked how this might be connected to the conductivity of a solution, they were stumped.

I'm not so sure that understanding how a conductivity probe works is essential knowledge for your average high schooler (I'm pretty sure it ain't...), but I was struck with the disconnect that existed from physics to chemistry for these very bright students. This, it seems to me, is exactly the focus of Mark's poster presentation. Beginning a high school science sequence with a Modeling-centered physics course in ninth grade can create a foundation of knowledge, language, methods, thinking skills and representational tools that can be called on (and built upon further) throughout a student's high school science classes. Furthermore, a constant conversation between teachers in different subjects through this transition and beyond can help build courses that emphasize the interconnectedness of concepts in science. The students in this chemistry class had taken physics, but not through a Modeling approach. While I wouldn't necessarily suggest that a Modeling curriculum would have better prepared these students to infer that a flow of ions must be responsible for the "conductivity" they measured, I do certainly think that better consistency between courses could have helped students to connect these concepts. Similarly, representations developed in the Models of Light unit could be used with representations of energy quanta developed the in chemistry class to build a more nuanced understanding of photosynthesis in Biology class the following year. As the Modeling method expands to include more resources in chemistry and biology, a transition to Modeling within a department has increasing potential to encourage this continuity.

I may be putting words in Mark's mouth, so please go talk to him in person at the Houston Hall Bistro tonight (Monday) at 8:30!!

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